Universal joint

Abstract

The joint includes first and second parts, each of which is operatively connected to a different one of two shafts. The parts are relatively movable about a given point in accordance with the angular movement of the shafts relative to each other and are rotatable in accordance with the rotation of the shafts. Each of the parts comprises a pair of radially spaced arcuate fingers which mesh with the corresponding fingers of the other part. One of the fingers on each part is provided with a slot. The slots align radially when the fingers mesh. A pin is provided, extending through the slots to connect the parts for simultaneous rotation and to permit relative movement between the pin and the parts, respectively. The other finger on each part is provided with a gear rack. A beveled idler gear, mounted on the pin, meshes with the gear racks simultaneously and is rotatable as the parts and thus the racks are moved relative to each other. The degree of rotation of the gear is a function of the movement between the parts and causes the pin to move relative to the parts. This movement maintains the pin at a position equally distant from the axes of the shafts. As long as this position is maintained, torque is transmitted from one shaft to another at uniform angular velocity, regardless of the angular position of the shafts relative to each other.

I claim: 
     
       1. A joint for transmitting torque at the uniform angular velocity between a first and a second rotatable shaft angularly movable relative to each other, said joint comprising first and second parts operatively connected to said first and second shafts, respectively, said parts being relatively movable about a given point in accordance with the angular movement of said shafts relative to each other and rotatable in accordance with the rotation of said shafts, each of said parts comprising two pairs of articulate fingers situated in diametrically opposed relationship to each other, each pair of fingers on one part meshing with the corresponding pair of fingers on the other part as the parts are angularly moved, means for operably connecting said parts for simultaneous rotation thereof, means on each of said parts for slidably mounting said connecting means thereto to permit relative angular movement between said connecting means and each of said parts, respectively, and means for maintaining said connecting means at a position equidistant from the axis of said shafts throughout the range of angular movement thereof. 
     
     
       2. The joint of claim 1 further comprising second connecting means, one of said connecting means cooperating with each corresponding pair of fingers. 
     
     
       3. A joint for transmitting torque at a uniform angular velocity between first and second rotatable shafts which are angularly movable relative to each other, said joint comprising first and second parts, each of said parts comprising a body portion, each of said body portions being operatively connected to a different one of said shafts and a pair of arcuate fingers extending outwardly from said portion, said fingers being spaced from each other such that said finger pair on one part meshes with the finger pair on the other part as said parts are moved about a given point in accordance with the angular movement of said shafts relative to each other, one finger from each pair being provided with a slot therein, a pin extending through said slots, the other finger from each pair being provided with gear teeth, a gear mounted on said pin and meshing with the gear teeth on each of said other fingers, said pin causing said parts to rotate simultaneously as said shafts are rotated, said gear causing said pin to remain equidistant from the axes of the shafts as said shafts are angularly moved. 
     
     
       4. The joint of claim 3 wherein said given point is the point of intersection of the axes of said shafts. 
     
     
       5. The joint of claim 3 wherein said given point is the center of a series of successively smaller concentric spheres, each of said spheres being defined by the arcuate curve of the top and bottom surfaces of said fingers. 
     
     
       6. The joint of claim 3 wherein each of said parts has a second pair of arcuate fingers extending from said body in a direction opposite to said first pair, said fingers in said second pair being spaced from each other such that the second pair of fingers on one of said parts meshes with the second pair of fingers on the other of said parts, as said parts are moved about a given point in accordance with the angular movement of said shafts relative to one another, one finger from each of said second pair being provided with a slot therein, a second pair extending through said slots, the other finger from each of said second pair being provided with gear teeth, a second bevel gear mounted on said pin and meshing with each of said other fingers, said teeth on second finger causing said parts to rotate simultaneously as said shafts are rotated, said second bevel gear causing said second pin to remain equidistant from the axes of the shafts as said shafts are angularly moved. 
     
     
       7. The joint of claim 3 further comprising a sleeve through which said pin extends and a plurality of bearings situated within said sleeve between said pin and interior wall of said sleeve. 
     
     
       8. The joint of claim 7 wherein said sleeve has a square exterior configuration and a circular interior cross-section. 
     
     
       9. The joint of claim 3 further comprising a spacer washer mounted on said pin and extending at least partially between said one finger of each pair. 
     
     
       10. The joint of claim 9 wherein said washer has a square perimeter and is spherically curved to coincide with the spherical curvature of the top and bottom surfaces of said fingers.